The BAU travels to Long Beach, California, where several people have been killed by arsenic poisoning, but not before they are sent a handwritten note telling them about their imminent demise. Beyond some geographic similarities, there is seemingly no other ties between the victims. Based on statements by those who were with the victims either before their deaths or when they may have consumed the arsenic, the BAU believes they at least have a general physical description of the unsub, he being a heavy set fortyish man driving an older model green sedan. Later in the investigation, the BAU also finds that the unsub has been leaving pieces of twine on the victims, which leads to Reid figuring out that the unsub's modus operandi is based on Greek mythology. After they find the ties between the victims, the BAU will have to discover the unsub's stressor to discover his identity and potential future targets. Meanwhile, Hotch is concerned about the request for him to speak at Jack's third grade class' career day about life as an FBI profiler, especially as it is this job that directly was responsible for the death of Jack's mother.
—Huggo